Kyeong-Hoon Kim

Effect of harvest time and cultivars on forage yield and quality of whole crop barley.

Barley is an important substrate for forage production in winter season of Korea. In this study, field trials were carried out to investigate the effects of harvest time and cultivar on the yield and quality of forage barleys developed in Korea. Four whole crop barley cultivars (Youngyang, Wooho, Yuyeon and Dami) were selected and harvested on five separate growth stages (heading, and intervals of 1, 2, 3, and 4 weeks after heading) in split plot design with three replications. Forage yield and nutritive value were determined. Results from this experiment indicated significant differences due to harvest time and cultivar in dry matter yield and total digestible nutrients (TDN) yield for forage. The interaction between harvest time and cultivar was not significant. The TDN yield trends were increasing with later harvest time due to higher dry matter yield and TDN content. This experiment provides some interesting results with respects to optimum harvest time, feed value and ultimately yield for the different whole crop barley cultivars.

Effects of agronomic characteristics and grain morphology on pre-harvest sprouting in Korean wheat cultivar.

Pre-harvest sprouting (PHS), which is the precocious germination of the grains in the spike before it is harvest, is the serious problem in the reduction of end-use quality in wheat. In this study, the relationships among PHS tolerance, agronomic and grain characteristics in Korean wheat cultivars were evaluated for two years to improve PHS tolerance in Korean wheat breeding programs. Grain characteristics including 1,000 grain weight and grain size (length, width and thickness), PHS tolerance conducted by the mist spray in the humid chamber (PHS-MS) and germination index (GI), and Agronomic traits including heading date, maturing date, culm length, awn length and the number of grain/spike, were significantly influence by genotype, year and the interaction between year and genotype, except in spike length, the number of spike/m 2 and test weight. PHS tolerance and GI were significantly correlated with 1,000-grain weight (r = 0.618, and r = 0.528, respectively) and length, width and thickness of grain, although no significant relationship between agronomic traits and PHS tolerance was found in Korean wheat cultivars. PHS-MS also showed positively correlated with GI value (r = 0.770, P < 0.001). White grain cultivars showed higher PHS-MS and GI values (61.86% and 0.58, respectively) than red grain cultivars (11.89% and 0.18, respectively). White grain cultivars also showed higher values in length, width and thickness of grain than red grain cultivars. Among red grain cultivars, Alchan, Goso, Suan and Sukang showed lower values in both PHS-MS and GI (< 2.63% and < 0.05, respectively) and these cultivars could be used to improve PHS tolerance in Korean wheat breeding programs.

ISSR-derived Molecular Markers for Korean Wheat Cultivar Identification

Inter simple sequence repeat (ISSR) is a technique that leads to the development of novel specific molecular markers and relationship analysis between species. In this study, 54 ISSRs were used to develop cultivar-specific DNA sequence characterized amplified regions (SCARs) for Korean wheat cultivars (Triticum aestivum). Using nine of 54 UBC ISSR primers, 16 cultivar-specific fragments were detected among 32 wheat cultivars. Of the 16 primers, 10 successfully amplified targets in 32 cultivars and six novel cultivar-specific markers were finally selected. A total of 13 Korean wheat cultivars (Ol, Dahong, Namhae, Jinpum, Anbaek, Jopoom, Jokyung, Sinmichal 1, Jeokjoong, Dajung, Goso and Joah) were classified by newly developed six SCAR markers. Cultivar-specific markers can be used not only for cultivar fingerprinting but also for marker-assisted selection in wheat breeding program.

Comparative Pathogenicity of Fusarium graminearum Isolates from Wheat Kernels in Korea

Fusarium head blight (FHB) caused by Fusarium species is a major disease of wheat and barley around the world. FHB causes yield reductions and contamination of grains with trichothecene mycotoxins including; nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), and 15-acetylde-oxynivalenol (15-ADON). The objectives of this study were to identify strains of F. graminearum isolated in Korea from 2012-harvested wheat grain and to test the pathogenicity of these NIV- and DON-producing isolates. Three hundred and four samples of wheat grain, harvested in 2012 in Chungnam, Chungbuk, Gyeongnam, Jeonbuk, Jeonnam, and Gangwon provinces were collected. We recovered 44 isolates from the 304 samples, based on the PCR amplification of internal transcribed spacer (ITS) rRNA region and sequencing. Our findings indicate that F. asiaticum was the predominant (95% of all isolates) species in Korea. We recovered both F. asiaticum and F. graminearum from samples collected in Chungnam province. Of the 44 isolates recovered, 36 isolates had a NIV genotype while 8 isolates belonged to the DON genotype (3-ADON and 15-ADON). In order to characterize the pathogenicity of the strains collected, disease severity was assessed visually on various greenhouse-grown wheat cultivars inoculated using both NIV- and DON-producing isolates. Our results suggest that Korean F. graminearum isolates from wheat belong to F. asiaticum producing NIV, and both F. graminearum and F. asiaticum are not significantly different on virulence in wheat cultivars.

Effects on Growth and Yield Whole-crop Barley by Soil-borne Virus Infection

Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) cause severe diseases in winter barley in Europe and East Asia. We investigated the effect of different level of resistance to virus disease on the plant growth and yield in whole-crop barley. In the virus infection, BaYMV was detected all tested cultivars in first diagnosis at 30th March. BaYMV infection was identified only in the susceptible Sunwoobori in 6th April, but not in the Yuyeon (moderate, M) and Youngyang (moderate resistant, MR) cultivars. Plant height was restrained about 14.6~32.9% in overwintered plant regeneration stage depending on the resistance of each cultivar. The tiller numbers also reduced to 8.7~19.7% by BaYMV infection in overwintering season. We evaluated culm length, spike length, and spike number in the virus-infected field and non-infected field. For the culm length, Youngyang (MR) reduced only 14.5% by BaYMV. However Sunwoo (susceptible, S) and Yuyeon (M) cultivars were decreased to 24.8~42.7%. The spike length and spike number also affected to 8.9~21.3% and 24.3~31.0%, respectively, depending on the resistance. After harvesting, dry-matter yield of whole crop yield reduced by approximately 21.6~58.0% according to cultivar resistant degrees. For example, Sunwoobori (S) decreased 58.0% in comparing to non-infected field. The grain yield was also significantly reduced in virus infected cultivars. Sunwoobori (S) was severely decrease more than 60.0%. Yuyeonbori (M) and Youngyangbori (MR) also decreased 30.0~47.5% by the viral infection comparing to those in the non-infected field.